(CNN) Death is a certainty in life, but premature death has become less of a certainty in the United States, according to a new study.
Researchers compared the rates and causes of death in the U.S. population between 1969 and 2013 using death certificate data from the National Vital Statistics System. They focused on the top killers during this period: heart disease, cancer, chronic obstructive pulmonary disease, accidents, stroke and diabetes.
The researchers found that the overall death rate has dropped sharply (42.9%) over the last four decades. And all the leading causes of death, with the exception of chronic obstructive pulmonary disease, or COPD, claimed fewer lives in 2013 than in 1969.
"It is definitely very good news because rates have decreased and continue to decrease for the five major causes of death," said Ahmedin Jemal, vice president of the Surveillance and Health Services Research Program at the American Cancer Society. Jemal led the study, which was published on Tuesday in the journal JAMA.
"People have to die of something in older age, but we want to avoid premature death," Jemal said. Although heart disease (including heart attacks), stroke and cancer are still leading causes of death — and will probably continue to be for the "foreseeable future" — these conditions are responsible for fewer premature deaths, which the study defined as dying before age 75, he added.
The annual risk of dying due to heart disease, stroke, cancer, diabetes and accidents decreased by 67.5%, 77%, 17.9%, 16.5% and 39.8%, respectively, between 1969 and 2013.
There was even some hopeful news in the rate of deaths due to COPD. Although the rate increased steadily for women from 1969 to 2013 and for men from 1969 to 1985, the rate started to wane among men between 1999 and 2013, probably because many men had quit smoking, which is a major risk factor for the disease, Jemal said. Smoking prevalence has now also decreased among women and thus they will probably also have fewer COPD deaths in the coming decade, he added.
There are probably two main reasons why the major causes of death have become less deadly, Jemal said. One is that we have better treatments, such as medications for blood pressure and cholesterol, to stave off heart disease, stroke and diabetes; the other is that we have less exposure to risk factors, especially smoking, than in previous decades.
The current study, along with other research such as a report by the Centers for Disease Control and Prevention on mortality rates between 1935 and 2010, suggests that we are getting better at putting off some of the major causes of death. However there is still room for improvement.
The current study found the decrease in death rates has lessened for heart disease, stroke and diabetes in the last decade, which the authors suggest could be due to the rise in obesity. "We can do more to accelerate the decrease in mortality rates by applying what we know in prevention broadly and in all populations," including reducing obesity, smoking and alcohol consumption, and increasing exercise and healthy eating, Jemal said
For death rates to come down even further will probably require more local programs that encourage healthy living in communities and for individuals, said Dr. J. Michael McGinnis, a senior scholar at the National Academy of Medicine, who wrote an editorial about the study for JAMA.
The current study did not capture a number of disturbing trends, such as the sharp rise in the prevalence of Alzheimer's disease (which has overtaken diabetes as the sixth leading cause of death) and the recent increase in diabetes deaths, McGinnis said.
There are also many important measures of health besides death, such as quality of life and health care access, and in particular the gap in health care quality among whites and blacks, that need to be addressed in future studies, McGinnis said.
Although the current study did not take a close look at individual racial groups, the trend of decreasing mortality rates did seem to hold for all races, Jemal said.